1. Field of the Invention
The present invention relates to a communication apparatus for communication with a communication network, an image pickup apparatus for inter-apparatus communication, a communication apparatus for communication with the image pickup apparatus, a control method therefor, and a storage medium for storing a control program.
2. Description of the Related Art
Recently, due to the progress of semiconductor technology, etc., portable radio communication apparatuses have become widespread. Communication using cellular phones as portable radio communication apparatuses is shifting from calls made to a person to calls made to a number.
In addition to voice communication, the portable radio communication apparatuses implement a text mail function and an easy Web browser function. To further improve the communication capacity of new-generation portable radio communication apparatuses, it is considered that an improvement in the capacity of an image photographing function and a communication function of the photographed image will become important.
Conventionally, after digitizing an image photographed by a camera, the digitized image is transferred to a telephone network by the portable radio communication apparatus. Recently, the communication speed of portable radio communication apparatuses and the picture quality of digital cameras of portable radio communication apparatuses have been improved in practice. In particular, the digital cameras have greatly improved picture quality and, for example, if printing a large-sized image, the digital camera photographs an image with a high picture quality which is substantially similar to that of a camera using a silver-halide film (film-based camera).
An image communication method in which the portable radio communication apparatus transfers an image of an object to a telephone network after digitizing it into image data, using a scanner, etc., and the transferred image is obtained by photographing the object using a camera, developing the image in a mini laboratory, etc., and printing the image, requires time and a number of operations. Accordingly, an image communication method for transferring, using the portable radio communication apparatus, digitized image data which is obtained by photographing the object with a digital camera is very efficient.
The above-mentioned image communication method using the digital camera and the portable radio communication apparatus responds to the trends of today's world such as various communication and multimedia demands.
However, the above image communication method using the digital camera and the portable radio communication apparatus has the following problems.
(1) If the line quality of the telephone network degrades when transferring the image data to the telephone network, that is, reception errors occurs, the number of re-transfers of the image data is increased, and it takes a long time for communication of the image data. In particular, when transferring a large amount of image data which requires a long time for communication, the image communication needs a much longer time. Consequently, there is a problem in that a specific radio frequency or a specific channel is exclusively used for a long time (in other words, is necessarily used) and power (battery) consumption is increased.
(2) If a large amount of image data is transferred when the data-transfer capacity of the telephone network is small (i.e., a low data-transfer speed), the image communication needs a much longer period of time. Consequently, there is a problem in that a specific radio frequency or a specific channel is exclusively used for a long time (in other words, is necessarily used) and power (battery) consumption is increased.
(3) If transferring a large amount of image data causes a radio unit to operate for a long time in a status in which the amount of remaining battery power in the portable radio communication apparatus is low, there is a problem in that the load on the battery is increased, thus further degrading the battery, and a decrease in voltage of the circuit causes an erroneous operation of the circuit and, then, the communication is disconnected.